Palletizers of this kind are known. Such a palletizer provides an empty pallet in a loading station for the purpose of loading said pallet. Packages, e.g. bottle crates, single-use packages or the like, are deposited, in layers, on said pallet. To this end, the packages are lifted from a package providing station by means of a gripper head and placed on the empty or already partially loaded pallet. For transporting the packages, e.g. a rotary column provided with one or two vertically adjustable gripper heads is used. For the purpose of unloading, the above-described method takes place in reverse order. Especially when two gripper heads are used, a comparatively high throughput can be accomplished.
In spite of optimized loading and unloading of the packages with the aid of two gripper heads, the use of these known loading and unloading methods and known palletizers entails the problem that, as soon as a pallet has been fully loaded or unloaded, down times will occur during the exchange of pallets, i.e. when a new empty pallet or a new fully packed pallet are being provided. During such down times, the package providing station can neither deposit nor remove any packages and is therefore inevitably inoperative.